Blower Motor Power Module: Operation

WARNING: This page is about a different car, the 2005 Dodge Grand Caravan, 2005 Dodge Caravan, and 2005 Chrysler Town & Country. However, it is still accessible from the selected car via links, so may be relevant.

The rear blower motor power module is connected to the vehicle electrical system through a dedicated lead and connector of the rear HVAC wire harness. A second connector receptacle receives the wire harness connector from the rear blower motor. The rear blower motor power module allows the microprocessor-based automatic temperature control (ATC) A/C-heater control to calculate and provide infinitely variable blower motor speeds based upon either manual blower switch input or the ATC programming using a pulse width modulated (PWM) circuit strategy.

The PWM voltage is applied to a comparator circuit which compares the PWM signal voltage to the rear blower motor feedback voltage. The resulting output drives the power module circuitry, which adjusts the voltage output received from the rear blower motor relay to change or maintain the desired blower speed.

The rear blower motor power module is diagnosed using a DRBIII® scan tool. Refer to BODY DIAGNOSTIC PROCEDURES .

The rear blower motor power module cannot be adjusted or repaired and, if faulty or damaged, it must be replaced.